class_docstr: Unit tests for the LangChain wrapper LLM class
code: def test_langchain_llm_type(self, langchain_llm):
      langchain_wrapper = LangchainLLM(langchain_llm)
  
      assert langchain_wrapper.type == "langchain_openai"
  
file_path: pandas-ai/tests/llms/test_langchain_llm.py
imports: from langchain.llms import OpenAI
  import pytest
  from pandasai.llm import LangchainLLM
  from pandasai.prompts import AbstractPrompt
  from unittest.mock import Mock
label_desc: Use image node_id 3 for calling the TestLangchainLLM obj's underlying member method code with example usage: obj.test_langchain_llm_type(langchain_llm) without return types